What are vitamins classified as in terms of their role in nutrition?
პასუხი
(A)
Essential nutrients
2
Which of the following best describes Vitamin A (retinal) from a chemical perspective?
პასუხი
(B)
A compound containing a cyclohexenyl ring
3
What enzyme is responsible for breaking down β-Carotene, a Vitamin A precursor?
პასუხი
(A)
An enzyme involved in dioxygenation
4
In the intestinal lining, what cofactor is required by retinaldehyde reductase to convert retinal to retinol?
პასუხი
(A)
A form of NADPH
5
Which of the following foods is a significant source of preformed Vitamin A?
პასუხი
(A)
Dairy products, fats, and organ meats
6
The conversion between retinol and retinal necessitates the presence of a dehydrogenase or reductase, which, in turn, requires which of the following cofactors?
პასუხი
(A)
NAD or NADP
7
What is a characteristic of fat-soluble vitamins?
პასუხი
(D)
All of the above
8
What is the standard used to define one international unit of Vitamin A?
პასუხი
(A)
The activity of 0.3 µg of Vitamin A alcohol
9
At what temperature does Lumirhodopsin remain stable?
პასუხი
(D)
Below -50°C
10
In the bloodstream, how is retinol transported?
პასუხი
(A)
Bound to a specific binding protein
11
What is the typical blood serum level of vitamin A, measured in mg per 100 ml?
პასუხი
(B)
15-60
12
Which of the following is a symptom associated with a lack of vitamin A?
პასუხი
(B)
Night blindness
13
A deficiency in Vitamin A can lead to which condition?
პასუხი
(A)
Xeropthalmia
14
What is a key role that vitamin A plays in the body?
პასუხი
(D)
To maintain the integrity of epithelial tissue
15
Which visual pigment contains retinal as a key component?
პასუხი
(B)
Rhodopsin
16
In what process does retinoic acid take part?
პასუხი
(C)
Glycoprotein
17
What form of retinal results when rhodopsin is exposed to light?
პასუხი
(A)
All trans-retinal
18
The Carr-Price reaction is utilized for identifying which vitamin?
პასუხი
(A)
Vitamin A
19
The following structure represents which of the following substances?
პასუხი
(A)
Cholecalciferol
20
Under what condition is the absorption of Vitamin D enhanced?
პასუხი
(A)
Acid pH of intestine
21
Which of the following is the most active form of Vitamin D in the body?
პასუხი
(B)
1,25-Dihydroxycholecalciferol
22
What is the typical range for 25-hydroxycholecalciferol levels in a blood test, measured in ng/ml?
პასუხი
(D)
8-55
23
What is the normal range for 1,25-dihydroxycholecalciferol in the blood, expressed in pg/ml?
პასუხი
(A)
26-65
24
What is the typical concentration of 24,25-dihydroxycholecalciferol in the blood, measured in ng/ml?
პასუხი
(C)
1-5
25
Which of the following is NOT a good source of Vitamin D?
პასუხი
(C)
Milk
26
Which of the listed options contains the highest concentration of Vitamin D?
პასუხი
(A)
Fish liver oils
27
A lack of Vitamin D can lead to which of these conditions?
პასუხი
(A)
Rickets and osteomalacia
28
The biological activity of one international unit (I.U) of vitamin D is equivalent to how much cholecalciferol?
პასუხი
(A)
0.025 µg of cholecalciferol
29
What type of light causes the breakdown of the ẞ-ring of 7-dehydrocholesterol, leading to the production of cholecalciferol?
პასუხი
(C)
Ultraviolet irridation with sunlight
30
Which organs are involved in the synthesis of calcitriol?
პასუხი
(A)
Both liver and kidney
31
Which substance contains a negligible amount of Vitamin E?
პასუხი
(D)
Fish liver oil
32
What factor negatively impacts the effectiveness of tocopherols?
პასუხი
(A)
Commercial cooking
33
Increased intake of which dietary component elevates the need for vitamin E?
პასუხი
(C)
Polyunsaturated fat
34
Which mineral's demand is lowered by vitamin E?
პასუხი
(C)
Selenium
35
Which of the following is considered a key natural antioxidant?
პასუხი
(B)
Vitamin E
36
What process do tocopherols inhibit?
პასუხი
(A)
Vitamin A oxidation
37
Creatinuria is linked to a shortage of which vitamin?
პასუხი
(C)
E
38
Which scenario does NOT lead to a true or apparent lack of vitamin K?
პასუხი
(B)
Total lack of red meat in the diet
39
Where is vitamin K primarily sourced from?
პასუხი
(A)
Green leafy plants
40
What is a primary function of Vitamin A?
პასუხი
(D)
All of these
41
From which source was Vitamin K initially extracted?
პასუხი
(D)
Putrid fish meal
42
Which vitamin is produced by bacteria in the intestines?
პასუხი
(D)
K
43
Vitamin K aids in modifying blood clotting factors by serving as a helper molecule for which enzyme?
პასუხი
(A)
Carboxylase
44
Vitamin K assists in which process?
პასუხი
(A)
Gamma carboxylation of glutamic acid residue
45
An excess of Vitamin K in newborns might lead to which condition?
პასუხი
(B)
Jaundice
46
Dicoumarol counteracts the effects of which vitamin?
პასუხი
(C)
Menadione
47
For those consuming large amounts of vitamin C, what is the typical serum ascorbic acid level?
პასუხი
(A)
1-1.4 µg/100 ml
48
Which vitamin is most likely to be lacking in someone following a diet exclusively consisting of meat?
პასუხი
(C)
Vitamin C
49
Where is the highest concentration of ascorbic acid found in the human body?
პასუხი
(B)
Adrenal cortex
50
Which vitamin is essential for creating hydroxyproline (in collagen)?
